It took Western Digital's HGST subsidiary more than a decade to develop a way to reliably seal helium gas inside of a hard drive. It was worth the wait.

HGST Monday announced that it's now shipping a helium-filled, 3.5-in hard disk drive with 50% more capacity than the current industry leading 4TB drives. The new drive uses 23% less power and is 38% lighter than the 4TB drives.

Without changing the height, the new 6TB Ultrastar He6 enterprise-class hard drive crams seven disk platters into what was a five disk-platter, 4TB Ultrastar drive.

A comparison between HGST's 4TB Ultrastar drive and the new 6TB Ultrastar He6 enterprise-class hard drive

While HGST would not release specific pricing for the drives, as they will be sold to server and storage array manufactures, the company did say the drives will "command a premium" not just based on capacity, the lower total cost of ownership that the helium technology offers.

"I'd say helium is one of the major breakthroughs in the hard drive industry because you can only increase the platter areal density so much with today's technology," said Fang Zhang, an analyst at market researcher IHS.

While the Ultrastar He6's 50% boost in capacity is impressive, what's most notable is the power reduction, Zhang said, because the high-capacity drives will be used in large data centers and cloud infrastructures.

At one-seventh the density of air, helium produces less drag on the moving components of a drive - the spinning disk platters and actuator arms -- which translates into less friction and lower operating temperatures.

The helium-drives run at four to five degrees cooler than today's 7200rpm drives, HGST stated.

Sealing air out of the drive also keeps humidity and other contaminates from getting in.

Netflix, which uses HGST high-capacity hard drives in its data centers, said the increase in capacity and lower power-usage in the Ultrastar He6 hard drives will go a long ways toward optimizing their streaming video server infrastructure.

Netflix serves up billions of hours of streaming video per quarter to over 40 million subscribers requires a constant effort to optimize server infrastructure, according to David Fullagar, director of Content Delivery Architecture at Netflix.

"As part of our efforts to optimize the delivery ecosystem for Netflix and our Internet Service Provider partners, we strive to build better and better streaming appliances. The high storage density and lower power usage of the Ultrastar He6 hard drives allow us to continue with that goal, and create a great customer experience," Fullagar said.

HGST said it's been working with key computer manufacturers, cloud and research groups, including HP, Huawei Unified Storage, Green Revolution Cooling, Code42, CERN as well as some of the world's largest social media and search companies, to qualify the drive.

"Data is going to the moon. As we deploy solutions that are tens and hundreds of petabytes, anything you can do to increase density is a boon," said Jimmy Daley, director of Smart Storage at Hewlett-Packard. "We are seeing about 2-watt lower power on random workloads compared to today's 4TB. That's about 20% [power reduction]."

Daley is currently testing more than a dozen of HGST's He6 6TB drives in HP's SL4500 servers, and expects hundreds of the drives to be in the servers by the end of the month.

The SL4500 servers hold up to 60 drives each. Previously, the SL4500 server, using 4TB drives, could hold a quarter of a petabyte, or 250TB of data; the box could potentially hold one-third of a petabyte, or about 333TB of data with the 6TB drives.

"To me, it is a clear indication of how important density is," Daley said. "Density translates into reduction of footprint."